Quick Answer: What Is @Controller In Spring Boot?

What is a controller class in spring boot?

@Controller annotation indicates that the annotated class is a controller.

It is a specialization of @Component and is autodetected through classpath scanning.

It is typically used in combination with annotated handler methods based on the @RequestMapping annotation..

What is difference between @controller and @RestController in spring boot?

Difference between @RestController and @Controller in Spring. … The @Controller is a common annotation that is used to mark a class as Spring MVC Controller while @RestController is a special controller used in RESTFul web services and the equivalent of @Controller + @ResponseBody.

What is use of @autowired in spring?

Autowiring feature of spring framework enables you to inject the object dependency implicitly. It internally uses setter or constructor injection. Autowiring can’t be used to inject primitive and string values. It works with reference only.

What is @RequestMapping annotation in spring?

@RequestMapping is one of the most widely used Spring MVC annotation. … annotation. RequestMapping annotation is used to map web requests onto specific handler classes and/or handler methods. @RequestMapping can be applied to the controller class as well as methods.

What is @RequestParam in spring boot?

@RequestParam is a Spring annotation used to bind a web request parameter to a method parameter. It has the following optional elements: defaultValue – used as a fallback when the request parameter is not provided or has an empty value.

What is Requestbody?

This is used to convert the body of the HTTP request to the java class object with the aid of selected HTTP message converter. This annotation will be used in the method parameter and the body of the http request will be mapped to that method parameter.

What is value in @RequestMapping?

value method is an alias for path method. This is an alias for path(). For example @RequestMapping(“/foo”) is equivalent to @RequestMapping(path=”/foo”). So both methods are similar in that sense.

What is @PostMapping in spring boot?

@PostMapping annotation maps HTTP POST requests onto specific handler methods. It is a composed annotation that acts as a shortcut for @RequestMapping(method = RequestMethod.

What is @ResponseBody annotation in spring?

@ResponseBody is a Spring annotation which binds a method return value to the web response body. It is not interpreted as a view name. It uses HTTP Message converters to convert the return value to HTTP response body, based on the content-type in the request HTTP header.

Why controller is used in spring?

@Controller annotation is an annotation used in Spring MVC framework (the component of Spring Framework used to implement Web Application). The @Controller annotation indicates that a particular class serves the role of a controller. … This class perform the business logic (and can call the services) by its method.

What is the difference between @RequestBody and @RequestParam?

@RequestParam makes Spring to map request parameters from the GET/POST request to your method argument. @RequestBody makes Spring to map entire request to a model class and from there you can retrieve or set values from its getter and setter methods.

What is the difference between @PathParam and @PathVariable?

The @PathVariable annotation is used for data passed in the URI (e.g. RESTful web services) while @RequestParam is used to extract the data found in query parameters. These annotations can be mixed together inside the same controller. @PathParam is a JAX-RS annotation that is equivalent to @PathVariable in Spring.

What is @controller in Java?

MVC Pattern stands for Model-View-Controller Pattern. This pattern is used to separate application’s concerns. Model – Model represents an object or JAVA POJO carrying data. It can also have logic to update controller if its data changes.

What is RequestMapping?

@RequestMapping is one of the most common annotation used in Spring Web applications. This annotation maps HTTP requests to handler methods of MVC and REST controllers. In this post, you’ll see how versatile the @RequestMapping annotation is when used to map Spring MVC controller methods.

What is difference between @PathVariable and @RequestParam in spring?

1) The @RequestParam is used to extract query parameters while @PathVariable is used to extract data right from the URI. … Even though both are used to extract data from URL, @RequestParam is used to retrieve query parameters, anything after ? in the URL, while @PathVariable is used to retrieve values from URI itself.